1. Field of the Invention
The present invention relates to a micro-scheduling method, and more particularly, to a micro-scheduling method for implementation on an operating system that supports multimedia applications. The present application is based upon Korean Application No. 99-27887, which is incorporated herein by reference.
In addition, the present invention relates to an operating system kernel for implementing the above micro-scheduling method.
2. Description of the Related Art
Operating systems such as UNIX((trademark)), LINUX ((trademark)), and Windows NT ((trademark)) use a task scheduling method, which has a time window of about 10 milliseconds, for supporting multiple users. In order to support multimedia applications, functions that satisfy Quality of Service (QoS) requirements must be supported in an operating system and a network. However, if a plurality of applications are processed, continuous interruptions occur according to a set task scheduling, even during the processing of multimedia data, thereby interrupting the processing of multimedia or causing it to be discontinuous. That is, scheduling methods used in conventional operating systems have a drawback in that they cannot satisfy the QoS requirements for supporting multimedia applications.
Another conventional technology to solve the above problem uses a method of modifying a process structure, for example, making a shared heap. This method has a drawback in that such modification causes loss of compatibility with existing software.
If a real-time scheduling algorithm is applied according to a third conventional technology to solve the above problem, it can cause a substantial drop in performance due to admission control, maintaining backward compatibility, and severe reduction of the QoS. It can also cause a problem in which a previously guaranteed service quality cannot be achieved in an overload state.
In order to solve the above problems, an objective of the present invention is to provide a micro-scheduling method to satisfy the QoS requirements for supporting multimedia applications.
Another objective of the present invention is to provide an operating system kernel to implement the above micro-scheduling method.
Accordingly, to achieve the above objective of the invention, there is provided a micro-scheduling method for implementation on an operating system kernel for supporting multimedia applications. The micro-scheduling method includes the steps of determining performance parameters of a plurality of applications by measuring an I/O-bound job performance and a CPU-bound job performance in the applications. Second, the performance parameters according to a policy set by a system administrator when carrying out job admission control are adjusted appropriately. Third, the processing priority of each of a plurality of application classes, by scheduling a periodical execution of I/O jobs of data that do not require to be moved to a user space due to characteristics of multimedia application data is determined. Finally, a special I/O system call according to an order of priority decided in the previous step is executed.
In order to achieve another objective of the invention, there is provided an operating system kernel for supporting multimedia applications. The operating system kernel includes an enterprise QoS (E-QoS) resource managing means for determining performance parameters by measuring I/O-bound job performance and CPU-bound job performance in a given application, and carrying out job admission control to adjust the performance parameter appropriately according to a policy set by a system administrator. A special I/O scheduling means for scheduling the periodical execution of I/O jobs of data which does not need to be moved to a user space due to the characteristics of multimedia applications; and a special I/O service routine means for carrying out a special I/O system call according to the order of priority set by the special I/O scheduling means is provided.